[swift-evolution] Thoughts regarding readable INTENT of Loop keywords

[Taras Zakharko]

I do not see how this is more readable. The current for loop is perfectly readable and conveys the intent very well IMO: it executes a code block FOR every ELEMENT that is IN a SEQUENCE. In contrast, I find your proposal rather confusing: it combines a number of different constructions with different semantics and generally is less transparent. 

Best, 

 Taras

> On 30 Mar 2016, at 21:54, Nathanial Burton-Bradford via swift-evolution <swift-evolution at swift.org> wrote:
> 
> Swift Control Flow using Loops 
> 
> One of Swifts strengths is clear, readable INTENT, conveyed by the languages Keyword tokens. For anyone new to programming, clear, readable intent, goes a long way in helping them master the language, by helping reduce logical/semantic errors caused by a misunderstanding of the names used in specifying the languages keyword tokens…
> Swift’s control flow keywords can be ambiguous, in this respect, when conveying the functional intent of loop control logic, within the language.
> 
> I would like to open up discussion, therefore, regarding the possible renaming of Swift’s control flow keywords, with the hope that this leads to clearer INTENT regarding loops. 
> 
> 
> Replace For-In with Loop Using 
> 
> for foo in d…y 
> loop foo using d…y
> 
> For x in 1…5
> loop x using 1…5
> 
> loop i=0 using i<10
> 
> loop i using 0..<10
> 
> 
> 
> For _ in 1 …power
> ———->
> loop using 1…power
> 
> “The underscore character (_) used in place of a loop variable causes the individual values to be ignored and does not provide access to the current value during each iteration of the loop.”
> 
> I feel underscore character (_) is confusing, semantically. 
> 
> 
> let names = ["Anna", "Alex", "Brian", “Jack"]
> for name in names {
> ———-> loop names using name {
>     print("Hello, \(name)!")
> }
> 
> Note : loop ARRAY using ELEMENT(S) - which is logically consistent with ‘-using’ as last keyword instance.
> 
> let numberOfLegs = ["spider": 8, "ant": 6, "cat": 4]
> for (animalName, legCount) in numberOfLegs {
>     print("\(animalName)s have \(legCount) legs")
> }
> 
> loop numberOfLegs using (animalName, legCount) {
> print(“ \(animalName)s have \(legCount) Legs”)
> }
> 
> Note : Again loop ARRAY using ELEMENT(S) - which is logically consistent with ‘-using’ as last keyword instance.
> 
> 
> for (airportCode, airportName) in airports {
> loop airports using (airportCode, airportName) 
> for airportCode in airports.keys {
> loop airports.keys using airportCode {
>    
> for airportName in airports.values {
> loop airports.values using airportName {
> 
> for value in array[1..<array.count] {
> loop array[1..<array.count] using value
> 
> ‘while’ using loop while 
> 
> loop while square < finalSquare {
>     // roll the dice
>     diceRoll += 1
>     if diceRoll == 7 { diceRoll = 1 }
>     // move by the rolled amount
> 
> Control transfer statements
> 
> repeat { 
> ——> loop {
> …
> } while 
> 
> 
> “Break
> The break statement ends execution of an entire control flow statement immediately. ”
> 
> I propose replacing Break, in loops, with exit now (intent is explicit)
> Note: Labeled Statements with break - 
> break gameLoop exit now gameLoop
> 
> “Continue
> The continue statement tells a loop to stop what it is doing and start again at the beginning of the next iteration through the loop.”
> 
> “switch character {
>     case "a", "e", "i", "o", "u", " ":
>         continue // Continue what? to next line? to end? to beginning?
>     default:
>         puzzleOutput.append(character)
>     }”
> 
> I propose replacing continue with next cycle or next loop
> 
> 
> “switch character {
>     case "a", "e", "i", "o", "u", " ":
>         next cycle // intent is explicit
>     default:
>         puzzleOutput.append(character)
>     }”
> 
> Note: Labeled Statements with Continue - as per Break example, next cycle gameLoop 
> 
> 
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